Ink set, ink jet recording apparatus, ink jet recording method, recording unit, and ink cartridge

ABSTRACT

The present invention provides an ink set, an ink jet recording apparatus, an ink jet recording method, a recording unit, and an ink cartridge, which can produce ink jet color images in which the color balance does not easily become unstable even if the image is stored for a long time, and in which the color images have greater durability so that degradation of the visual appearance is not easily recognizable even if the image is stored for a long time. The ink set includes a first aqueous ink and a second aqueous ink having the same color tone, the second ink having a lower coloring material content than that of the first ink, and the degree of fading of an image produced with the second ink is the same as or lower than that of an image produced with the first ink.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to ink sets, and more particularly,relates to an ink set that is suitable for use in ink jet recording inwhich an ink is ejected from an orifice in response to a recordingsignal in order to perform recording on a recording medium, as well asto an ink jet recording apparatus, an ink jet recording method, arecording unit, and an ink cartridge.

[0003] 2. Description of the Related Art

[0004] Conventionally, aqueous inks in which dyes having various colortones are dissolved in water-soluble media are used for color recordingusing an ink jet recording method. It is desirable that the inks exhibitthe following ink jet recording characteristics (1) to (10) at as high adegree as possible.

[0005] (1) Produces images with adequate density;

[0006] (2) Satisfactorily dries on a recording medium;

[0007] (3) Smearing of the recorded image does not occur;

[0008] (4) Running of the recorded image does not occur when in contactwith water, alcohols, etc.;

[0009] (5) A recorded image with superior light-fastness is produced;

[0010] (6) Does not cause clogging at nozzles;

[0011] (7) Blurring of recorded images does not occur during continuousprinting or when recording is started after a long interval;

[0012] (8) Stable when stored;

[0013] (9) Problems do not occur even if inks are brought into contactwith components of the recording apparatus; and

[0014] (10) Has superior heat resistance and does not affect thermalenergy generation elements.

[0015] Furthermore, as demand for color ink jet recording increases,images of higher resolution and higher quality are being required. Forthese purposes, color images in the broad color reproduction range areachieved by selecting coloring materials having superior colordeveloping ability, and the dot size of images is decreased by producingsmall ink droplets, thereby achieving images with high resolution.Furthermore, by using two or more types of inks which have differentcoloring material contents but the same color tone, the inks can beselected depending on the density of the image, i.e., light colorportions and deep color portions, and by controlling variousink-applying processes, it is possible to produce smoother images. Usingthe techniques described above, ink jet recording methods have recentlybeen producing ink jet images of high quality, which are comparable tosilver halide photographs.

[0016] However, even if ink jet images of a quality comparable to silverhalide photographs are produced using the techniques described above,the color balance may become unstable depending on the environment inwhich the images are stored and the visual appearance of the image maydegrade, resulting in a loss in durability of the images. Therefore,there is an increased demand for an ink jet image which has, in additionto high resolution, even more superior durability, for example, andwhich does not fade substantially even if stored for a long period oftime.

SUMMARY OF THE INVENTION

[0017] Accordingly, the present invention provides an ink set which canproduce a color image that is able to maintain good color balance for along period of time in which the color balance does not easily becomeunstable even if stored for a long time.

[0018] The present invention also provides an ink jet recording methodand an ink jet recording apparatus used therefor, which can producecolor images having greater durability, i.e., degradation of the visualappearance of the image is not easily recognizable even if stored for along time.

[0019] The present invention provides a magenta ink set capable ofsuppressing changes in the visual color balance due to the degradationof the magenta color in images even if stored for a long time.

[0020] The present invention also provides a recording unit and an inkcartridge which can be used very effectively for the production of inkjet color images in which image degradation due to the degradation ofthe magenta color in images is not easily noticeable.

[0021] According to one aspect of the present invention, there isprovided an ink set comprising a first aqueous ink and a second aqueousink having the same color tone, wherein the first and second inkscontain at least one common coloring material, the second ink has alower coloring material content than the coloring material content ofthe first ink, and the degree of fading of an image produced with thesecond ink is the same as or lower than the degree of fading of an imageproduced with the first ink.

[0022] According to another aspect of the present invention, there isprovided an ink set comprising a first aqueous ink and a second aqueousink having the same color tone, wherein the first and second inkscontain at least one common coloring material, the second ink has alower coloring material content than the coloring material content ofthe first ink, and the residual rate of the reflection density of animage produced with the second ink when it is left under a conditionthat promotes fading is equal to or greater than that of an imageproduced with the first ink.

[0023] By using the ink sets as described above, it is possible toobtain color images in which the color balance does not becomesubstantially unstable even if the image is stored for a long time.

[0024] According to a further aspect of the present invention, there isprovided an ink jet recording apparatus comprising ink storage portionsstoring a first aqueous ink and a second aqueous ink having a same colortone respectively, wherein the first ink and the second ink contain atleast one common coloring material, the second ink has a lower coloringmaterial content than the coloring material content of the first ink,and the degree of fading of an image produced with the second ink is thesame as or lower than the degree of fading of an image produced with thefirst ink, and a head portion for ejecting the inks.

[0025] According to a further aspect of the present invention, there isprovided an ink jet recording apparatus comprising ink storage portionsstoring a first aqueous ink and a second aqueous ink having a same colortone respectively, wherein the first ink and the second ink contain atleast one common coloring material, the second ink has a lower coloringmaterial content than the coloring material content of the first ink,and the residual rate of the reflection density of an image producedwith the second ink when it is left under a condition that promotesfading is equal to or greater than that of an image produced with thefirst ink, and a head portion for ejecting the inks.

[0026] According to a further aspect of the present invention, there isprovided an ink jet recording method comprising the step of applying afirst aqueous ink and a second aqueous ink having the same color tone toa recording medium, wherein the first and second inks contain at leastone common coloring material, the second ink has a lower coloringmaterial content than the coloring material content of the first ink,and the degree of fading of an image produced with the second ink is thesame as or lower than the degree of fading of an image produced with thefirst ink.

[0027] According to a further aspect of the present invention, there isprovided an ink jet recording method comprising the step of applying afirst aqueous ink and a second aqueous ink having the same color tone toa recording medium, wherein the first ink and the second ink contain atleast one common coloring material, the second ink has a lower coloringmaterial content than that of the first ink, and the residual rate ofthe reflection density of an image produced with the second ink when itis left under a condition that promotes fading is equal to or greaterthan the residual rate of reflection density of an image produced withthe first ink when it is left under the same conditions.

[0028] By using the apparatuses and the methods as described above, itis possible to obtain ink jet color images in which the color balancedoes not become substantially unstable even if stored for a long time.

[0029] According to a further aspect of the present invention, there isprovided an ink set comprising a first ink and a second ink having thesame color tone, wherein the second ink has a lower coloring materialcontent than the coloring material content of the first ink, the secondink is an aqueous ink containing a dye represented by the formula (I)below as a sole coloring material, and the first ink is an aqueous inkcontaining a dye represented by the formula (I) below and at least oneof a dye represented by the formula (II) below and a dye represented bythe formula (III) below, as coloring materials.

[0030] In formula (I), R₁ is a substituted or unsubstituted alkoxy groupor a substituted or unsubstituted aryl group; each of R₂ and R₄ isindependently a hydrogen atom or a substituted or unsubstituted alkylgroup; R₃ is selected from the group consisting of a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedalkoxy group, a substituted or unsubstituted aryloxy group, and ahalogen atom; X₁ is a carboxyl group or a salt thereof, or a sulfonicacid group or a salt thereof; and n is 1 or 2.

[0031] In formula (II), Ar₁ is a substituted or unsubstituted phenylgroup, or a substituted or unsubstituted naphthyl group; Ar₂ is selectedfrom the group consisting of an acetyl group, a benzoyl group, a1,3,5-triazinyl group, a SO₂—C₆H₅ group, and a SO₂—C₆H₄—CH₃ group; and Mis selected from the group consisting of a hydrogen atom, an alkalimetal, an ammonium, and an organic ammonium, M being a counter ion ofthe sulfonic acid group.

[0032] In formula (III), each of Ar₃ and Ar₄ is independently asubstituted or unsubstituted phenyl group, or a substituted orunsubstituted naphthyl group, at least one of Ar₃ and Ar₄ having acarboxyl group or a salt thereof, or a sulfonic acid group or a saltthereof; M is selected from the group consisting of a hydrogen atom, analkali metal, an ammonium, and an organic ammonium, M being a counterion of the sulfonic acid group; R₅ is a 1,3,5-triazinylene group; eachof R₆ and R₇ is independently selected from the group consisting of ahydrogen atom, a substituted or unsubstituted alkyl group, a substitutedor unsubstituted alkenyl group, a substituted or unsubstituted aralkylgroup, and an atomic group necessary to complete a perhydroxyazine ringtogether with N; and L is a bivalent organic connecting group.

[0033] According to a further aspect of the present invention, there isprovided an ink set comprising a first ink and a second ink having thesame color tone, wherein the second ink has a lower coloring materialcontent than the coloring material content of the first ink, the secondink is an aqueous ink containing a dye represented by formula (I) as asole coloring material, and the first ink is an aqueous ink containing adye represented by formula (I) and at least one of C. I. Acid Red 52 andC. I. Acid Red 289.

[0034] By using the first and second inks containing the coloringmaterials described above, it is possible to obtain color images havingsuperior durability in which degradation over time due to thedegradation of an image with magenta inks is inhibited.

[0035] According to a further aspect of the present invention, there isprovided an ink jet recording apparatus comprising ink storage portionsstoring a first ink and a second ink having a same color tonerespectively, wherein the second ink has a lower coloring materialcontent than the coloring material content of the first ink, the secondink is an aqueous ink containing a dye represented by formula (I) as asole coloring material, and the first ink is an aqueous ink containing adye represented by formula (I) and at least one of a dye represented byformula (II) and a dye represented by formula (III), as coloringmaterials, and a head portion for ejecting the inks.

[0036] According to a further aspect of the present invention, there isprovided an ink jet recording apparatus comprising ink storage portionsstoring a first ink and a second ink having a same color tonerespectively, wherein the second ink has a lower coloring materialcontent than the coloring material content of the first ink, the secondink is an aqueous ink containing a dye represented by formula (I) as asole coloring material, and the first ink is an aqueous ink containing adye represented by formula (I) and at least one of C. I. Acid Red 52 andC. I. Acid Red 289, and a head portion for ejecting the inks.

[0037] According to a further aspect of the present invention, there isprovided an ink jet recording method comprising the step of applying afirst ink and a second ink having the same color tone to a recordingmedium, wherein the second ink has a lower coloring material contentthan that of the first ink, the second ink is an aqueous ink containinga dye represented by formula (I) as a sole coloring material, and thefirst ink is an aqueous ink containing a dye represented by formula (I)and at least one of a dye represented by formula (II) and a dyerepresented by formula (III), as coloring materials.

[0038] According to a further aspect of the present invention, there isprovided an ink jet recording method comprising the step of applying afirst ink and a second ink having the same color tone to a recordingmedium, wherein the second ink has a lower coloring material contentthan that of the first ink, the second ink is an aqueous ink containinga dye represented by formula (I) as a sole coloring material, and thefirst ink is an aqueous ink containing a dye represented by formula (I)and at least one of C. I. Acid Red 52 and C. I. Acid Red 289, ascoloring materials.

[0039] By using the ink sets, the ink jet recording apparatuses, and theink jet recording methods described above, it is possible to obtain inkjet color images having superior durability in which degradation of theimage over time due to the degradation of an image with the magenta inksis inhibited.

[0040] According to a still further aspect of the present invention,there is provided a recording unit comprising an ink container sectioncontaining inks, and a head section for ejecting the inks, wherein theinks constitute any one of the represented ink sets used for an ink jetprinter.

[0041] According to a still further aspect of the present invention,there is provided an ink cartridge comprising an ink container sectioncontaining inks, wherein the inks constitute any one of the representedink sets.

[0042] Further objects, features and advantages of the present inventionwill become apparent from the following description of the preferredembodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0043]FIG. 1 is a longitudinal sectional view of a head section of anink jet recording apparatus;

[0044]FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1;

[0045]FIG. 3 is a perspective view of a head section of an ink jetrecording apparatus;

[0046]FIG. 4 is a perspective view showing an ink jet recordingapparatus;

[0047]FIG. 5 is a longitudinal sectional view of an ink cartridge;

[0048]FIG. 6 is perspective view of a recording unit;

[0049]FIG. 7 is a schematic diagram showing an ink cartridge in anembodiment of the present invention;

[0050]FIG. 8 is a schematic diagram showing a recording head providedwith the ink cartridge shown in FIG. 7;

[0051]FIG. 9 is a schematic diagram showing a recording unit in anembodiment of the present invention;

[0052]FIG. 10 is a schematic perspective view showing a key portion ofan ink jet printer on which a liquid ejection head can be mounted;

[0053]FIG. 11 is a schematic perspective view showing an ink jetcartridge provided with a liquid ejection head;

[0054]FIG. 12 is a schematic perspective view showing a key portion of aliquid ejection head;

[0055]FIG. 13 is a conceptual diagram showing a portion of a liquidejection head;

[0056]FIG. 14 is an enlarged view of an ejection port shown in FIG. 13;

[0057]FIG. 15 is a schematic diagram showing the ink adhesion state atthe ejection port shown in FIG. 14;

[0058]FIG. 16 is a schematic diagram showing a key portion of a liquidejection head;

[0059]FIG. 17 is a sectional view taken along line 17-17 of FIG. 16,which schematically shows the liquid ejection operation of the liquidejection head with time;

[0060]FIG. 18 is a sectional view taken along line 17-17 of FIG. 16,which schematically shows the liquid ejection operation of the liquidejection head with time;

[0061]FIG. 19 is a sectional view taken along line 17-17 of FIG. 16,which schematically shows the liquid ejection operation of the liquidejection head with time;

[0062]FIG. 20 is a sectional view taken along line 17-17 of FIG. 16,which schematically shows the liquid ejection operation of the liquidejection head with time;

[0063]FIG. 21 is a sectional view taken along the line 17-17 of FIG. 16,which schematically shows the liquid ejection operation of the liquidejection head with time;

[0064]FIG. 22 is a sectional view taken along line 17-17 of FIG. 16,which schematically shows the liquid ejection operation of the liquidejection head with time;

[0065]FIG. 23 is a sectional view taken along line 17-17 of FIG. 16,which schematically shows the liquid ejection operation of the liquidejection head with time; and

[0066]FIG. 24 is a sectional view taken along line 17-17 of FIG. 16,which schematically shows the liquid ejection operation of the liquidejection head with time.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0067] The present invention will be described in more detail withreference to the preferred embodiments.

[0068] In view of the technical background with respect to the relatedart described above, the present inventors have carried out research inorder to produce ink jet color images having superior durability. It hasbeen found that fading proceeds more rapidly in a light color sectionhaving allow coloring material content; namely, with respect to an imageproduced by two inks having the same color tone with different coloringmaterial contents, even when coloring materials having the samelight-fastness are used for both inks, in the portion of the imageproduced using the light color ink, fading tends to become moreconspicuous than in the portion using the deep color ink. Consequently,the color balance becomes unstable in the whole image, and there tendsto be significant degradation of the visual appearance of the image.This tendency is particularly noticeable in the portions of the image inwhich light and deep magenta inks are used.

[0069] Furthermore, when a photo-like image is formed, in order toobtain smooth gradation, the half tone portion of the image is usuallyformed using a large amount of light color ink. As a method formaintaining the tone continuity between the deep color portion and thelight color portion, at least one common coloring material is containedin both the deep color ink and the light color ink having differentcoloring material contents. In contrast, the present inventors havefound that in order to improve the durability of an ink jet image insuch a situation, it is important to bring the durability of an imageproduced by the deep color ink and the durability of an image producedby the light color ink into balance. Namely, it is very important howthe deep color ink and the light color ink are combined. In a photo-likeink jet image in which image degradation is particularly easilynoticeable, in order to further improve the durability of the image, itis very important to discover the optimum combination of light and deepcolor inks. The present invention has been achieved based on suchfindings. In this context, fading means fading due to light.

[0070] Japanese Patent Laid-Open No. 2-127482 discloses a recordingmethod for providing images having superior light-fastness and clarityusing known inks having different coloring material contents, in which adeep magenta ink and a light magenta ink contain different dyes.However, the above-mentioned document does not describe the particulartechnical problems that arise when one common coloring material iscontained in the deep color ink and the light color ink in view of thetone continuity between the deep color portion and the light colorportion, nor does it disclose any means for solving such problems. As aresult of research by the present inventors, it has been found that amagenta coloring material having an anthrapyridone skeleton representedby formula (I) exhibits light-fastness far exceeding that of the dyeused for the light color ink disclosed in Japanese Patent Laid-Open No.2-127482, and even when the magenta coloring material is used for a deepcolor ink, images having both superior light-fastness and clarity areprovided.

[0071] Japanese Patent Laid Open Nos. 59-74173 and 2-16171, etc.disclose magenta aqueous inks containing dyes having an anthrapyridoneskeleton, and describe that the dyes have superior light-fastness.Japanese Patent Laid Open Nos. 57-197191 and 2000-169776 also discloseink jet color printing methods using magenta aqueous inks containingdyes having an anthrapyridone skeleton. However, these documents do notdisclose mixing of the anthrapyridone-based magenta dyes and othermagenta dyes, and moreover, do not even suggest improvement inlight-fastness of images produced by inks containing a mixture of aplurality of inks. Furthermore, the documents do not describe theattempt to make higher image quality and improvement in light-fastnesscompatible with each other by using two or more inks having the samecolor tone with different image densities.

[0072] In a first embodiment of the present invention, when two inkshaving different coloring material contents are used for producing acolor image, a first aqueous ink and a second aqueous ink are used. Thefirst ink and the second ink have at least one common coloring material,the second ink has a lower coloring material content than that of thefirst ink, and the degree of fading of the second ink is the same as orlower than that of the first ink.

[0073] As described above, the present inventors have found that, withrespect to an image produced by two inks having the same color tone withdifferent coloring material contents, fading proceeds more rapidly inthe light color section having a low coloring material content, and evenwhen coloring materials having the same light-fastness are used for bothinks, in the portion of the image produced using the light color ink,fading is more conspicuous. Consequently, the color balance becomesunstable in the whole image, and there tends to be significantdegradation of the visual appearance of the image. Therefore, in orderto inhibit this phenomenon, in the present invention, when an ink setincluding a first aqueous ink and a second aqueous ink having the samecolor tone and containing at least one common coloring material isprepared, the degree of fading of an image produced with the second inkhaving a low coloring material content is set to be the same as or lowerthan that of an image produced with the first ink having a high coloringmaterial content.

[0074] Herein, the meaning of “the degree of fading of an image producedwith the second ink is the same as or lower than that of an imageproduced with the first ink” is that the fading rate of the image withthe second ink is the same as or lower than that of the image with thefirst ink.

[0075] In a second embodiment of the present invention, when two inkshaving different coloring material contents are used for producing acolor image, a first aqueous ink and a second aqueous ink are used. Thefirst ink and the second ink contain at least one common coloringmaterial, the second ink has a lower coloring material content than thatof the first ink, and the residual rate of the reflection density of animage produced with the second ink when left under certain predeterminedconditions that promote fading is equal to or greater than the residualrate of the reflection density of an image produced with the first inkwhen left under such predetermined conditions. The residual rates of thereflection density of images produced with the first and second inks arepreferably 80% or more.

[0076] Herein, examples of the predetermined conditions that promotefading include irradiation with a xenon lamp at approximately 6,000klux·hr. That is, when ink images are left under such conditions, fadingoccurs in the ink images, and reflection densities decrease, resultingin visual image degradation. Therefore, in the present invention, whenan ink set including a first aqueous ink and a second aqueous ink havingthe same color tone and containing at least one common coloring materialis prepared, a first ink having a high coloring material content and asecond ink having a low coloring material content are combined so that adecrease in the residual rate of the reflection density of an imageobtained by the second ink having a relatively low coloring materialcontent is equal to or greater than the decrease in the residual rate ofthe reflection density of an image obtained by the first ink having arelatively high coloring material content when left under certainconditions in which image degradation is likely to occur.

[0077] In order to satisfy such a relationship between the first andsecond inks, an ink set in which coloring materials in the first andsecond inks are appropriately selected may be used. For example, an inkset in which the first ink contains at least two coloring materials maybe used. When the relevant ink set has a cyan tone, for example, as onecommon coloring material for the first and second inks, C. I. DirectBlue 199 may be used, and as another coloring material for the firstink, C. I. Acid Blue 9 may be used. Alternatively, C. I. Acid Blue 307may be used as one common coloring material, and as a second coloringmaterial for the first ink, C. I. Acid Blue 9 may be used.

[0078] When the relevant ink set has a yellow tone, for example, as onecommon coloring material for the first and second inks, C. I. DirectYellow 86 may be used, and as another coloring material for the firstink, C. I. Acid Yellow 23 may be used. Alternatively, C. I. DirectYellow 132 may be used as one common coloring material, and as anothercoloring material for the first ink, C. I. Acid Yellow 23 may be used.

[0079] Next, ink sets having a magenta tone will be described below.

Coloring Material

[0080] Although the coloring material which can be used for the ink setin the present invention is not particularly limited, preferred examplesof the coloring materials include aqueous xanthene dyes,triphenylmethane dyes, anthraquinone dyes, monoazo dyes, disazo dyes,trisazo dyes, tetraazo dyes, and copper phthalocyanine dyes, all ofwhich are listed in the Color Index.

[0081] Preferred examples of the coloring material commonly used for thefirst and second magenta inks include an anthrapyridone-based dyerepresented by formula (I) below.

[0082] In the formula (I), R₁ is a substituted or unsubstituted alkoxygroup or a substituted or unsubstituted aryl group; each of R₂ and R₄ isindependently a hydrogen atom or a substituted or unsubstituted alkylgroup; R₃ is selected from the group consisting of a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedalkoxy group, a substituted or unsubstituted aryloxy group, and ahalogen atom; X₁ is a carboxyl group or a salt thereof, or a sulfonicacid group or a salt thereof; and n is 1 or 2.

[0083] With respect to R₁ to R₄, more specifically, for example, R₁ is astraight-chain or branched alkoxy group with 1 to 4 carbon atoms, or asubstituted or unsubstituted phenyl group. Examples of the substitutedphenyl group include a methyl group, a hydroxyl group, a nitro group, asulfonic acid group or a salt thereof, a carboxyl group or a saltthereof, and a halogen atom, such as fluorine, chlorine, or bromine. Forexample, R₂ is a hydrogen atom, or a straight-chain or branched loweralkyl group with 1 to 4 carbon atoms, and R₃ is a hydrogen atom, astraight-chain or branched alkyl group with 1 to 4 carbon atoms, astraight-chain or branched alkoxy group with 1 to 4 carbon atoms, or anaryloxy group such as a phenoxy group. The aryl group constituting thearyloxy group may be, for example, replaced with a straight-chain orbranched alkyl group with 1 to 10 carbon atoms, a sulfonic acid group ora salt thereof, a carboxyl group or a salt thereof, or the like.Furthermore, for example, R₄ is a hydrogen atom, or a straight-chain orbranched lower alkyl group with 1 to 4 carbon atoms. Specific examplesof X₁ include —COOM, —SO₃M, where M is a hydrogen atom, an alkali metal,such as Li and Na, an ammonium (NH₄), and an organic ammonium (N(R₈)₄),where R₈ is a methyl group, an ethyl group, or the like.

[0084] Examples of dyes which can be used for adding to the first inktogether with the coloring materials described above include a xanthenedye, such as at least one dye selected from the group consisting of C.I. Acid Red 52, C. I. Acid Red 289, etc., and at least one dye selectedfrom the dyes represented by formulae (II) and (III) below, or both. Inparticular, when a dye represented by formula (I), a dye represented byformula (II), and C. I. Acid Red 289 are combined as coloring materialsin the first ink, the image produced with the ink has a superior magentacolor tone, which is, coupled with the effect of inhibiting a change incolor balance, particularly advantageous for the formation of photo-likecolor images.

[0085] In formula II, Ar₁ is a substituted or unsubstituted phenylgroup, or a substituted or unsubstituted naphthyl group; Ar₂ is selectedfrom the group consisting of an acetyl group, a benzoyl group, a1,3,5-triazinyl group, a SO₂—C₆H₅ group, and a SO₂—C₆H₄—CH₃ group; and Mis selected from the group consisting of a hydrogen atom, an alkalimetal such as Li and Na, an ammonium (NH₄), and an organic ammonium(N(R₉)₄), where R₉ is a methyl group, an ethyl group, or the like, Mbeing a counter ion of the sulfonic acid group. The phenyl group or thenaphthyl group of Ar₁ may be replaced with, for example, at least onegroup or atom selected from the group consisting of a carboxyl group ora salt thereof, a sulfonic acid group or a salt thereof, astraight-chain or branched alkyl group with 1 to 4 carbon atoms, ahalogen atom, such as fluorine, chlorine, or bromine, an alkoxy groupwith 1 to 4 carbon atoms, and an aryloxy group, such as a phenoxy group.When Ar₂ is a benzoyl group or a 1,3,5-triazinyl group, at least onehydrogen atom in the benzene ring or the 1,3,5-triazine ring may bereplaced with a carboxyl group or a salt thereof, a halogen atom, suchas fluorine, chlorine, or bromine, a primary amino group, a secondaryamino group, a tertiary amino group, an alkoxy group, a hydroxyl group,or the like.

[0086] In formula III, each of Ar₃ and Ar₄ is independently asubstituted or unsubstituted phenyl group, or a substituted orunsubstituted naphthyl group. Examples of the substituted phenyl groupand naphthyl group include a straight-chain or branched alkyl group with1 to 4 carbon atoms, a straight-chain or branched alkoxyl group with 1to 4 carbon atoms, a hydroxyl group, a carboxyl group or a salt thereof,a sulfonic acid group or a salt thereof, and a halogen atom, such asfluorine, chlorine, or bromine. At least one of Ar₃ and Ar₄ has acarboxyl group or a salt thereof, or a sulfonic acid group or a saltthereof. M is selected from the group consisting of a hydrogen atom, analkali metal such as Li and Na, an ammonium (NH₄), and an organicammonium (N(R₁₀)₄), where R₁₀ is a methyl group, an ethyl group, or thelike, M being a counter ion of the sulfonic acid group. R₅ is a1,3,5-triazinylene group, at least one hydrogen atom in the1,3,5-triazine ring may be replaced with a carboxyl group or a saltthereof, a halogen atom, such as fluorine, chlorine, or bromine, aprimary amino group, a secondary amino group, a tertiary amino group, analkoxy group, a hydroxyl group, or the like. Each of R₆ and R₇ isindependently selected from the group consisting of a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedalkenyl group, a substituted or unsubstituted aralkyl group, and anatomic group necessary to complete a perhydroxyazine ring together withN. L is a bivalent organic connecting group. Specific examples of R₆ andR₇ include a straight-chain or branched alkyl group with 1 to 6 carbonatoms, a straight-chain or branched alkenyl group with 1 to 4 carbonatoms, and a benzyl group. Examples of the substituents of the alkylgroup, the alkenyl group, and the benzyl group include a hydroxyl group,a carboxyl group or a salt thereof, and a sulfonic acid group or a saltthereof.

[0087] As specific examples of the first coloring material representedby formula (I), which are preferably used in the present invention,illustrative compounds I-1 to I-7 are shown below. However, the presentinvention is not limited to these coloring materials. Two or more ofthese coloring materials may be used simultaneously.

[0088] Specific examples of the compounds represented by the formula(II), which are preferably used as coloring materials in the presentinvention, include C. I. Reactive Red 180, illustrative compounds II-8to II-13 of which structures are shown below, and compounds of whichstructures are shown in Japanese Patent Laid-Open Nos. 8-73791 and11-209673.

[0089] Examples of the compounds represented by formula (III), which arepreferably used as coloring materials in the present invention, includeillustrative compounds III-14 to III-22, of which the structures areshown below.

[0090] In the first magenta ink, the weight ratio of the coloringmaterial represented by formula (1) to the rest of the coloring materialis preferably set in the range of 95:5 to 20:80 in consideration of theadvantage that clear tones, high image densities, and superiorlight-fastness are obtained.

[0091] Additionally, with respect to the individual inks used in thepresent invention, regardless of the color tones of the inks, in thedeep color ink of the first ink having a high coloring material content,the total content of all coloring materials in the ink is preferably1.0% to 15.0% by weight of the total amount of the first ink, and in thelight color ink of the second ink having a low coloring materialcontent, the total content of all coloring materials in the ink ispreferably 0.1% to 5.0% by weight of the total amount of the second ink.

Aqueous Medium

[0092] The individual inks used in the present invention are aqueousinks containing the coloring materials as described above and aqueousmedia, which may contain a water-soluble organic solvent. Thewater-soluble organic solvent contained in the aqueous medium used isnot particularly limited. Examples of the water-soluble organic solventinclude alcohols, polyhydric alcohols, polyglycols, glycol ethers, polarsolvents containing nitrogen, and polar solvents containing sulfur. Thecontent of these water*soluble solvents in the ink is preferably 1% to40% by weight of the total amount of ink, and more preferably, 3% to 30%by weight, in consideration of maintenance of moisture in the ink,improvement in the solubility of the coloring materials, effectivepermeation of the ink into the recording paper, etc. The content ofwater in the ink is preferably 30% to 95% by weight so that satisfactorysolubility of the dyes as coloring materials in the ink is exhibited,sufficient viscosity of the ink for stable ink ejection is exhibited,and clogging does not occur at nozzles.

pH

[0093] The pH of each ink used in the present invention is notparticularly limited, as long as the solubility of the coloringmaterials is satisfied. However, in view of safety, etc., the preferredpH is in the range of 4.0 to 11.0.

Additives

[0094] When the individual inks used in the present invention areprepared, in order to maintain moisture in the ink, moisture-maintainingconstituents, such as urea, urea derivatives, and trimethylolpropane,may be used as ink constituents. The content of suchmoisture-maintaining constituents in the ink is preferably 0.1% to 20.0%by weight of the total amount of the ink, and more preferably, 3.0% to10.0% by weight. Furthermore, the individual inks used in the presentinvention may further contain, as necessary, other various additives,such as surfactants, pH regulators, rust preventives, preservatives,mildew-proofing agents, antioxidants, anti-reducing agents, evaporationaccelerators, chelating agents, and water-soluble polymers.

[0095] The inks used for the ink sets in the embodiments of the presentinvention are particularly suitable for an ink jet recording method inwhich recording is performed by the ejection of liquid droplets by theaction of thermal energy. Of course, the inks may also be used for othertypes of ink jet recording methods and for general writing implements.

Recording Apparatus, Ink Cartridge, and Recording Unit

[0096] As a suitable recording apparatus for performing recording usingthe ink set of the present invention, an ink jet recording apparatus ofthe present invention may be mentioned, in which thermal energy inresponse to recording signals is applied to inks stored in chambers of arecording head, and liquid droplets are generated.

[0097] FIGS. 1 to 3 show structural examples of recording heads.

[0098] A head 13 includes a plate composed of glass, ceramic, or plasticprovided with an ink passage 14, and a heat generation head 15 bondedthereto. The heat generation head 15 includes a protective film 16composed of a silicon oxide or the like, aluminum electrodes 17-1 and17-2, heat generation resistor layer 18 composed of nichrome or thelike, a heat accumulation layer 19, and a substrate 20 composed of amaterial with satisfactory heat dissipation, such as alumina. An ink 21is filled up to an ink ejection orifice (fine port) 22, and a meniscus23 is formed due to pressure. When an electrical signal is applied tothe electrodes 17-1 and 17-2, an area n rapidly generates heat, creatingbubbles in the ink 21 in contact with the area n. The meniscus 23 isdischarged through the orifice 22 to form recording liquid droplets 24,which are ejected toward a recording medium 25. FIG. 3 shows a schematicdiagram of a recording head provided with multiple passages 26 in whichmany nozzles, each as shown in FIG. 1, are arrayed. The recording headis fabricated by bonding a glass plate 27 provided with many passagesand a heat generation head 28, which is similar to that described withreference to FIG. 1, together. Additionally, FIG. 1 is a sectional viewof the head 13 taken along the ink passage, and FIG. 2 is a sectionalview taken along line 2-2 of FIG. 1.

[0099]FIG. 4 is a perspective view showing an example of an ink jetrecording apparatus in which a head as described above is used. A blade61, which acts as a wiping member, has a cantilever structure in whichone end is held by a blade-holding member. The blade 61 is disposedadjacent to the region recorded by the recording head, and is held so asto protrude in the moving course of the recording head. A cap 62 isdisposed at the home position adjacent to the blade 61, and moves in adirection perpendicular to the moving direction of the recording headand abuts the ejection surface for performing capping. An ink absorbent63 is held so as to protrude in the moving course of the recording headin the same manner as that of the blade 61.

[0100] The blade 61, the cap 62, and the ink absorbent 63 constitute anejection recovery section 64, and moisture, dust, etc. on the inkejection surface are removed by the blade 61 and the absorbent 63.

[0101] Numeral 65 represents a recording head having an ejection energygeneration means for ejecting an ink to a recording medium facing theejection surface and is provided with an ejection port. Numeral 66represents a carriage for carrying the recording head 65. The carriage66 is slidably engaged with a guide shaft 67, and a part of the carriage66 is connected to a belt 69 driven by a motor 68. Thereby, the carriage66 moves along the guide shaft 67 so that the recording head 65 moves inthe recording region and its adjacent region.

[0102] Numeral 51 represents a paper feed section for inserting-therecording medium, and numeral 52 represents a feed roller driven by amotor not shown in the drawing. In such a structure, the recordingmedium is fed to a position facing the ejection surface of the recordinghead 65, and as recording progresses, the recording medium is sent tothe discharge section provided with discharge rollers 53.

[0103] In the structure described above, when the recording head 65returns to the home position after recording is completed, although thecap 62 of the ejection recovery section 64 retreats from the moving pathof the recording head 65, the blade 61 protrudes toward the moving path.Consequently, the ejection surface of the recording head 65 is wiped.Additionally, when the cap 62 performs capping while abutting on theejection surface of the recording head 65, the cap 62 moves so as toprotrude toward the moving path of the recording head 65.

[0104] When the recording head 65 moves from the home position to thestarting position for recording, the cap 62 and the blade 61 are locatedat the same positions as those during wiping. Consequently, the ejectionsurface of the recording head 65 is also wiped when the recording head65 moves in such a way. Additionally, while the recording head 65 movesin the recording region for performing recording, the recording head 65moves to the home position adjacent to the recording region atpredetermined intervals, and wiping is also performed during such amove.

[0105]FIG. 5 is a sectional view showing an ink cartridge 45 whichcontains ink to be supplied to a head, for example, via a tube. The inkcartridge 45 includes an ink bag 40 as an ink container section, and astopper 42 composed of rubber provided on the tip of the ink bag 40. Theink in the ink bag 40 can be supplied to the head by inserting a needle(not shown in the drawing) into the stopper 42. Numeral 44 represents anink absorbent for absorbing waste ink. In the preset invention, each ofthe first ink and the second ink is filled in the ink container sectionof such an ink cartridge, and each ink cartridge is mounted on an inkjet printer provided with an ink jet recording head for ejecting theindividual inks, and image formation is performed, and thereby thesuperior effects of the present invention are achieved.

[0106]FIG. 7 shows an ink cartridge in another embodiment of the presentinvention, in which the first ink and the second ink constituting theink set of the present invention are separately filled. A cartridge 701includes two container sections 703 and 705 for containing the first inkand the second ink, respectively, and the cartridge 701 is detachablyfitted into an ink jet head 801 for ejecting the individual inksseparately, as shown in FIG. 8. When the cartridge 701 is fitted into arecording head 801, two types of ink having different coloring materialcontents are supplied to the recording head 801.

[0107] The ink jet recording apparatus of the present invention is notlimited to the one described above in which the recording head and theink cartridge are separately provided. An ink jet recording apparatus inwhich a recording head and an ink cartridge are integrated, as shown inFIG. 6, is also preferably used.

[0108] In FIG. 6, a recording unit 70 includes ink container sections inwhich the individual inks constituting the ink set of the presentinvention, for example, ink absorbents are contained, and the inks inthe ink absorbents are ejected from a head section 71 provided with aplurality of orifices. An air communicating opening 72 connects theinterior of the recording unit 70 with air. The recording unit 70 can beused instead of the recording head 65 shown in FIG. 4, and is detachablymounted on the carriage 66.

[0109] Furthermore, a recording unit in another embodiment of thepresent invention will be described, in which the first ink and thesecond ink constituting the ink set of the present invention arecontained in the respective ink container sections in an ink tank, andthe ink tank and a recording head for ejecting the individual inks areintegrally provided. Specifically, as shown in FIG. 9, a recording unit907 includes a container section 901 for containing the first ink, acontainer section 903 for containing the second ink, and a recordinghead 905 in which ink passages are separately provided so that theindividual inks are separately ejected.

[0110] Additionally, although the ink jet recording apparatus in whichink droplets are ejected by applying thermal energy to ink has beendescribed above, the present invention is also applicable to an ink jetrecording apparatus in which a piezoelectric element is used.

[0111] Next, other examples of the recording apparatus and the recordinghead which are preferably used in the present invention will bedescribed.

[0112]FIG. 10 is a schematic perspective view showing a liquid ejectionhead, in which bubbles are completely surrounded by air during ejection,and a key portion of an ink jet printer as a liquid ejection apparatususing the liquid ejection head. The ink jet printer shown in FIG. 10includes a casing 1008 containing a conveying device 1030 forintermittently conveying a recording sheet 1028 (recording medium),which is provided lengthwise, in the P direction shown in the drawing; arecording device 1010 which is reciprocated along a guide shaft 1014 ina direction substantially orthogonal to the conveying direction P of therecording sheet 1028 by the conveying device 1030; and a movementdriving device 1006 as a driving means for reciprocating the recordingdevice 1010.

[0113] The conveying device 1030 includes a pair of rollers 1022 a and1022 b, a pair of rollers 1024 a and 1024 b, and a driving unit 1020 fordriving the individual pairs of rollers. When the driving unit 1020 isoperated, the recording sheet 1028 is intermittently conveyed in the Pdirection while being sandwiched between the rollers 1022 a and 1022 band between the rollers 1024 a and 1024 b.

[0114] The movement driving device 1006 includes a belt 1016 placedaround pulleys 1026 a and 1026 b rotatably disposed with a predetermineddistance therebetween; and a motor 1018 for driving the belt 1016, whichis placed substantially parallel to the rollers 1022 a and 1022 b and isconnected with a carriage member 1010 a of the recording device 1010, inthe forward direction and the reverse direction.

[0115] When the motor 1018 is operated and the belt 1016 is rotated inthe R direction shown in FIG. 10, the carriage member 1010 a of therecording device 1010 is moved in the S direction by a predeterminedlength. When the motor 1018 is operated and the belt 1016 is rotated ina direction opposite to the R direction, the carriage member 1010 a ofthe recording device 1010 is moved in a direction opposite to the Sdirection by a predetermined length. Furthermore, on one end of themovement driving device 1006, a recovery unit 1026 for performingejection recovery treatment on the recording device 1010 is providedfacing the ink ejection port array of the recording device 1010.

[0116] The recording device 1010 is provided with ink jet cartridges(hereinafter may be referred to as cartridges) 1012Y, 1012M, 1012C, and1012B corresponding to yellow, magenta, cyan, and black, each detachablyplaced in the carriage member 1010 a.

[0117]FIG. 11 shows an ink jet cartridge which is mountable on the inkjet recording apparatus described above in an embodiment of the presentinvention. A cartridge 1012 is of a serial type, and includes an ink jetrecording head (liquid ejection head) 100 and a liquid tank 1001 forcontaining liquid, such as inks. The ink jet recording head 100 isprovided with a plurality of ejection ports 832 for ejecting liquid, andliquid, such as ink, is guided to a common liquid chamber (refer to FIG.12) of the liquid ejection head 100 via liquid supply passages (notshown in the drawing). In the cartridge 1012 shown in FIG. 11, the inkjet recording head 100 and the liquid tank 1001 are integrated, andliquid is supplied from the liquid tank 1001 as necessary. However, theliquid tank 1001 may be detachably connected to the liquid ejection head100.

[0118] The liquid ejection head which is mountable on the ink jetprinter as described above will be described in more detail.

[0119]FIG. 12 is a schematic perspective view showing a key portion of aliquid ejection head in an embodiment of the present invention, andFIGS. 13 to 15 are schematic diagrams showing the shape of the ejectionport section of the liquid ejection head shown in FIG. 12. Electricalwiring for driving electrothermal converting elements, etc. is omittedin the drawing.

[0120] As shown in FIG. 12, in the liquid ejection head, a substrate 934composed of glass, ceramic, plastic, metal, or the like is used. Thematerial for the substrate 934 is not particularly limited as long as itfunctions as a part of a liquid-passage-constituting member and as asupport for ink ejection energy generation elements and a material layerfor forming liquid passages and ejection ports. In this embodiment, asilicon substrate (wafer) is used as the substrate 934. The ejectionports may be formed by laser irradiation or by an aligner, such as amirror projection aligner (MPA), using an orifice plate (ejection portplate) 935 composed of a photosensitive resin.

[0121] As shown in FIG. 12, the substrate 934 is provided withelectrothermal converting elements (hereinafter may be referred to asheaters) 931 and an ink supply port 933, which is a through-hole shapedlike a long groove, as a common liquid chamber. Heaters 931 acting asthermal energy generation means are arrayed in a zigzag line on eachside of the ink supply port 933, for example, with a separation of 300dpi between heaters. The substrate 934 is provided with ink passagewalls 936 for forming ink passages. The ejection plate 935 provided withejection ports 832 is disposed on the ink passage walls 936.

[0122] Although the ink passage walls 936 and the ejection plate 935 areseparate members in the embodiment shown in FIG. 12, the ink passagewalls 936 and the ejection plate 935 may be integrally formedsimultaneously by spin coating or the like. In this embodiment, theupper surface 935 a of the ejection plate 935 is subjected towater-repellent finishing.

[0123] In this embodiment, a serial type head, which performs recordingwhile scanning in the S direction shown in FIG. 10, is used andrecording is performed, for example, at 1,200 dpi. The drive frequencyis 10 kHz, and ejection is performed at minimum time intervals of 100μs. As shown in FIG. 13, division walls 936 a for isolating fluidsejected by adjacent nozzles have a width W of 14 μm. As shown in FIG.16, liquid flow path 1338 has a bubble generation chamber 1337 formed bythe ink passage wall 936 with a width N₁ of 33 μm and a length N₂ of 35μm. The heater 931 has a size of 30 μm×30 μm, the heater resistance is53 Ω, and the drive voltage is 10.3 V. The ink passage wall 936 and thedivision wall 936 a have a height of 12 μm and the orifice plate 935 hasa thickness of 11 μm.

[0124]FIG. 14 is a sectional view of an ejection port 832 in an ejectionport section 940 shown in FIG. 12, taken in a direction orthogonal tothe direction in which ink is ejected (the thickness direction of theorifice plate 935). As shown in FIG. 14, the cross section of theejection port 832 is substantially star-shaped, and includes 6 convexsections 832 a with obtuse angles, and 6 concave sections 832 b withacute angles. The convex sections 832 a and the concave sections 832 bare arranged alternately. That is, 6 grooves 1141 are formed in thethickness direction of the orifice plate 935 (in the liquid ejectiondirection). The concave sections 832 b, which are further from thecenter O of the ejection port, correspond to the distal portions of thegrooves 1141, and the convex sections 832 a, which are closer to thecenter O of the ejection port, correspond to the proximal portions ofthe grooves 1141, as shown in FIG. 14.

[0125] In this embodiment, for example, the ejection port section 940has a cross section with a shape in which an equilateral triangle havingsides of 27 μm is laid over a similar triangle and rotated by an angleof 60 degrees. The length T₁ shown in FIG. 14 is 8 μm. Each convexsection 832 a has an angle of 120 degrees, and each concave section 832b has an angle of 60 degrees. Therefore, the center O of the ejectionport corresponds to the median point G of a polygon formed by linkingtogether the centers of the adjacent grooves, i.e., centers (medianpoints) of figures formed by linking the distal points of the grooveswith the two proximal points adjacent to the distal point. The openingarea of the ejection port 832 is 400 μm², and the opening area of onegroove 1141 (the area of the figure formed by linking the distal pointof the groove with the two proximal points adjacent to the distal point)is approximately 33 μm². FIG. 15 is a schematic diagram showing thestate of the adhesion ink (C) at the ejection port shown in FIG. 14.

[0126] Next, the liquid ejection operation by the ink jet recording headhaving the structure described above will be described with reference toFIGS. 17 to 24. FIGS. 17 to 24 are sectional views of the bubblegeneration chamber 1337, taken along the line 17-17 of FIG. 16. In thedrawings, the end of the ejection port section 940 in the thicknessdirection of the orifice plate 935 corresponds to the top part 1141 a ofthe groove 1141. FIG. 17 shows a state in which a film-like bubble isgenerated in the liquid or ink, designated as I, on the heater 931,FIGS. 18 to 24 show the states at approximately 1 μs, 2 μs, 3 μs, 4 μs,5 μs, 6 μs, and 7 μs after the state shown in FIG. 17, respectively.Additionally, the word “fall” or “sink” in the description below meansmovement toward the electrothermal converting element 931 regardless ofthe mounting direction of the head, and does not mean a fall in thedirection of gravity.

[0127] First, as shown in FIG. 17, as electric current is applied to theheater 931 based on a recording signal, etc., a bubble 101 is generatedin a liquid passage 1338 above the heater 931, and at approximately 1 to2 μs, the bubble 101 rapidly grows due to thermal expansion, as shown inFIGS. 18 and 19. When the bubble 101 is at its largest, the height ofthe bubble 101 exceeds the height of the ejection port surface 935 a,and at this stage, the pressure of the bubble decreases from theatmospheric pressure by several to several tens percent.

[0128] Next, approximately 2 μs after the generation of the bubble 101,the volume of the bubble 101 starts decreasing from the maximum, andalmost simultaneously, generation of a meniscus 102 starts. As shown inFIG. 20, the meniscus 102 retreats, i.e., falls, toward the heater 931.In this embodiment, as described above, since the ejection port sectionhas a plurality of grooves 1141, when the meniscus 102 retreats,capillary attraction acts on the groove 1141 in the F_(C) directionopposite to the retreating direction F_(M) of the meniscus 102. As aresult, even if variations occur in the state of the bubble 101 for somereason, when the meniscus 102 retreats, the shapes of the meniscus 102and a main liquid droplet (hereinafter may be referred to as liquid orink) I_(a) are corrected so as to be substantially symmetrical withrespect to the center of the ejection port.

[0129] Since the falling rate of the meniscus 102 is higher than thecontraction rate of the bubble 101, as shown in FIG. 21, approximately 4μs after the generation of the bubble, the bubble 101 separates from thelower surface of the ejection port 832 and is completely surrounded byair. At this stage, liquid (ink) in the vicinity of the central axis ofthe ejection port 832 sinks toward the heater 931. This is due to thefact that the liquid (ink) I_(a) which is pulled back toward the heater931 by a negative pressure of the bubble 101 before the bubble isconnected to air still maintains the velocity toward the heater 931 dueto inertia. As shown in FIG. 22, the liquid (ink) sinks toward theheater 931, reaches the surface of the heater 931 approximately 5 μsafter the generation of the bubble 101, and as shown in FIG. 23, theliquid spreads over the surface of the heater 931.

[0130] The lower portion of the liquid spreading over the surface of theheater 931 as described above has a vector directed along the surface ofthe heater 931, but loses a vector orthogonal to the surface of theheater 931, such as a vector directed normal to the surface of theheater 931, and stays on the surface of the heater 931, thereby pullingdown the upper portion of the liquid, i.e., the liquid having a velocityvector directed in the ejection direction. Subsequently, liquid I_(b)between the lower portion of the liquid spreading over the heater 931and the upper portion of the liquid (main liquid droplet) I_(a) becomesthinner, and as shown in FIG. 24, the liquid I_(b) is cut in the centerof the surface of the heater 931 approximately 7 μs after the generationof the bubble 101, and thus the main liquid droplet I_(a) having avelocity vector directed in the ejection direction is separated fromliquid I_(c) spreading over the surface of the heater 931. As describedabove, the position of the separation is preferably in the liquidpassage 1338, and more preferably, at the side of the electrothermalconverting element (heater) 931 rather than at the side of the ejectionport 832.

[0131] The main liquid droplet I_(a) is ejected from the center of theejection port 832 and hits a predetermined position on the surface ofthe recording medium, without a slant in the ejection direction. In aconventional liquid ejection head, the liquid I_(c) spreading over thesurface of the heater 931 is ejected as a satellite droplet after themain liquid droplet. However, in the present invention, the liquid I_(c)spreading over the surface of the heater 931 remains on the surface ofthe heater 931 and is not ejected. In such a way, since it is possibleto inhibit the ejection of the satellite droplet, spray which is likelyto occur due to the ejection of the satellite droplet can be avoided,and thus it is possible to reliably prevent the surface of the recordingmedium from being smeared by this spray. Additionally, in FIGS. 22 to24, symbol Id represents ink adhering to the groove (ink inside thegroove) and symbol I_(e) represents ink remaining in the liquid passage.

[0132] As described above, in the liquid ejection head in thisembodiment, when the liquid is ejected after the bubble grows largestand the volume of the bubble decreases, the direction of the main liquiddroplet can be stabilized by a plurality of grooves arranged around thecenter of the ejection port. Consequently, it is possible to provide aliquid ejection head which ejects the liquid without a slant so that theliquid hits the recording medium accurately. Since it is also possibleto stably eject the liquid with respect to variations in bubbling athigh drive frequencies, high speed, high definition printing is enabled.

[0133] In particular, since the liquid is ejected by completelysurrounding the bubble by air for the first time at the stage in whichthe volume of the bubble decreases, it is possible to prevent spray fromoccurring when the liquid droplet is ejected. Consequently, it ispossible to prevent the liquid droplet from adhering to the ejectionport surface, which may cause sudden non-ejection. Examples of therecording head in which bubbles are completely surrounded by air duringejection, which can be favorably used in the present invention, includea so-called “edge shooter type” recording head, such as the onedisclosed in Japanese Patent No. 2783647.

[0134] Next, the present invention will be described in more detail withreference to Examples and Comparative Examples. The contents of the inkingredients in the Examples and Comparative Examples are shown in partsby weight unless otherwise indicated.

EXAMPLES 1 TO 7 AND COMPARATIVE EXAMPLES 1 TO 6

[0135] The coloring materials and deionized water shown in Table 1 or 2below were added to the ingredients shown in the ink composition 1 belowso as to make the total 100 parts, followed by mixing. Using a 0.20 μmfilter, pressure filtration was performed, and ink sets in Examples 1 to7 and Comparative Examples 1 to 6, each containing two inks havingdifferent coloring material contents, were prepared. Ink Composition 1Glycerol  5.0 parts by weight Urea  5.0 parts by weight DiethyleneGlycol 10.0 parts by weight Acetylenol EH (manufactured by Kawaken  0.3part by weight Fine Chemicals Co., Ltd.) Ethanol  5.0 parts by weight

[0136] TABLE 1 Example 1 Example 2 Example 3 Example 4 C1 C1 C2 C2 Y1 Y1Y2 Y2 Light Deep Light Deep Light Deep Light Deep C.I. Acid 0.5 0.3 Blue9 C.I. Direct 1.5 3.5 Blue 199 C.I. Direct 2.0 3.5 Blue 307 C.I. Acid0.5 1.0 Yellow 23 C.I. Direct 1.2 2.5 Yellow 132 C.I. Direct 1.0 2.5Yellow 86 C.I. Acid Red 289 Deionized 73.2 70.7 72.7 70.9 73.7 71.7 73.571.2 water Example 5 Example 6 Example 7 M1 M1 M2 M2 M3 M3 Light DeepLight Deep Light Deep Illustrative 2.2 Compound I-3 Illustrative 1.0 1.52.5 Compound I-2 Illustrative 1.8 3.0 Compound I-7 Illustrative 1.0Compound II-8 Illustrative 1.6 Compound II-12 Illustrative 1.5 CompoundIII-21 C.I. Acid Red 0.1 289 Deionized water 73.7 70.9 73.2 70.7 72.970.6

[0137] TABLE 2 Comparative Comparative Comparative ComparativeComparative Comparative Example 1 Example 2 Example 3 Example 4 Example5 Example 6 C3 C3 C4 C4 Y3 Y3 Y4 Y4 M4 M4 M5 M5 Light Deep Light DeepLight Deep Light Deep Light Deep Light Deep C.I. Acid 1.5 4.0 Blue 9C.I. Direct 2.0 3.8 Blue 307 C.I. Acid 1.0 1.0 Yellow 23 C.I. Direct 2.0Yellow 132 C.I. Direct 1.0 3.5 Yellow 86 Illustrative 1.5 4.0 CompoundI-7 Illustrative 0.9 3.8 Compound II-8 Deionized 73.2 70.7 72.7 70.973.7 71.7 73.7 71.2 73.8 70.9 73.2 70.7 water

Evaluation

[0138] With respect to each of the ink sets obtained in Examples 1 to 7and Comparative Examples 1 to 6, printing was performed using anon-demand type ink jet printer having heat generation elements as energysources for ejecting ink. The resulting printed images were evaluatedwith respect to (1) light-fastness and (2) color developing abilityunder the conditions described below. The results thereof are shown inTable 3.

(1) Light-Fastness

[0139] A deep color ink having a higher coloring material content and alight color ink having a lower coloring material content constitutingthe ink set in each of the Examples and Comparative Examples were fittedinto the printer, and using the individual inks, solid images wereprinted on two recording media, i.e., a PPC paper (manufactured by CanonKabushiki Kaisha) and a glossy paper (PR-101 manufactured by CanonKabushiki Kaisha). The printed materials thus obtained were air-driedfor 24 hours, and using a xenon fade-meter Ci3000 (manufactured by AtlasCo.) provided with an ultraviolet cut filter, irradiation was performedfor 100 hours at a vessel temperature of 35° C., a humidity of 60% RH,and an irradiation intensity of 60 klux. The solid images of the printedmaterials were measured with a Macbeth Densitometer RD-918 before andafter the irradiation to find the residual rate of the reflectiondensity, and the light-fastness was evaluated based on the followingstandards.

(1-a)

[0140] A: The residual rate of the reflection density of the imageproduced by the deep color ink was 80% or more.

[0141] B: The residual rate of the reflection density of the imageproduced by the deep color ink was 60% or more to less than 80%.

[0142] C: The residual rate of the reflection density of the imageproduced by the deep color ink was less than 60%.

(1-b)

[0143] A: The residual rate of the reflection density of the imageproduced by the light color ink was equal to or higher than the residualrate of the reflection density of the image produced by the deep colorink.

[0144] B: The residual rate of the reflection density of the imageproduced by the light color ink was lower than the residual rate of thereflection density of the image produced by the deep color ink.

(2) Color Developing Ability

[0145] The deep color ink having a higher coloring material content ineach ink set was fitted into the printer, and solid images were printedon two recording media, i.e., a PPC paper (manufactured by CanonKabushiki Kaisha) and a glossy paper (PR-101 manufactured by CanonKabushiki Kaisha). The printed materials thus obtained were air-driedfor 24 hours, and the color developing ability thereof was visuallychecked based on the following standards.

[0146] AA: The color tone was significantly clear.

[0147] A: The color tone was clear.

[0148] B: The color tone was slightly dull. TABLE 3 Light-fastness (2)(1-a) (1-b) Color Deep Color Light Color Developing Ink Ink AbilityExample 1 A A A Example 2 A A A Example 3 A A A Example 4 A A A Example5 A A A Example 6 A A A Example 7 A A AA Comparative C B A Example 1Comparative A B B Example 2 Comparative B B A Example 3 Comparative A BB Example 4 Comparative B B A Example 5 Comparative A B B Example 6

[0149] Furthermore, using the inks in Examples 1 to 7, the printedmaterials used for the light-fastness evaluation were visually observedbefore and after the irradiation test. As a result, fading was notnoticeable either in the portion printed with the first ink having arelatively high coloring material content or in the portion printed withthe second ink having a relatively low coloring material content. Incontrast, with respect to the printed materials used in ComparativeExamples 1 to 6, since a change in color tone was partially observed dueto the fading of the portion printed with the second ink, fading of theimages after the test was noticeable. Consequently, it was found that inthe present invention, the difference in deterioration rate due to lightirradiation between the portion printed with the first ink and theportion printed with the second ink was relieved or overcome. It isobvious from the results described above that, in images produced withthe first and second inks constituting the ink set of the presentinvention, a change over time in color balance due to a difference indeterioration rate can be inhibited.

[0150] While the present invention has been described with reference towhat are presently considered to be the preferred embodiments, it is tobe understood that the invention is not limited to the disclosedembodiments. On the contrary, the invention is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims. The scope of the following claims is to beaccorded the broadest interpretation so as to encompass all suchmodifications and equivalent structures and functions.

What is claimed is:
 1. An ink set comprising a first aqueous ink and asecond aqueous ink having a same color tone, wherein the first ink andthe second ink contain at least one common coloring material, the secondink has a lower coloring material content than the coloring materialcontent of the first ink, and a degree of fading of an image producedwith the second ink is the same as or lower than a degree of fading ofan image produced with the first ink.
 2. An ink set comprising a firstaqueous ink and a second aqueous ink having a same color tone, whereinthe first ink and the second ink contain at least one common coloringmaterial, the second ink has a lower coloring material content than thecoloring material content of the first ink, and an image produced withthe second ink when it is left under a condition that promotes fadinghas a residual rate of reflection density that is equal to or greaterthan that of an image produced with the first ink.
 3. An ink setaccording to claim 2, wherein said condition comprises irradiation witha xenon lamp.
 4. An ink set according to any one of claims 1 to 3,wherein both the first ink and the second ink have a cyan tone.
 5. Anink set according to any one of claims 1 to 3, wherein both the firstink and the second ink have a yellow tone.
 6. An ink set according toany one of claims 1 to 3, wherein both the first ink and the second inkhave a magenta tone.
 7. An ink set according to claim 1 or 2, whereinthe first ink further contains another coloring material.
 8. An ink setaccording to claim 6, wherein the second ink contains a dye representedby formula (I) as a sole coloring material:

wherein R₁ is a substituted or unsubstituted alkoxy group or asubstituted or unsubstituted aryl group; each of R₂ and R₄ isindependently a hydrogen atom or a substituted or unsubstituted alkylgroup; R₃ is selected from the group consisting of a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedalkoxy group, a substituted or unsubstituted aryloxy group, and ahalogen atom; X₁ is a carboxyl group or a salt thereof, or a sulfonicacid group or a salt thereof; and n is 1 or
 2. 9. An ink set accordingto claim 6, wherein the first ink contains a dye represented by formula(I) and at least one of a dye represented by formula (II) and a dyerepresented by formula (III), as coloring materials:

wherein R₁ is a substituted or unsubstituted alkoxy group or asubstituted or unsubstituted aryl group; each of R₂ and R₄ isindependently a hydrogen atom or a substituted or unsubstituted alkylgroup; R₃ is selected from the group consisting of a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedalkoxy group, a substituted or unsubstituted aryloxy group, and ahalogen atom; X₁ is a carboxyl group or a salt thereof, or a sulfonicacid group or a salt thereof; and n is 1 or 2;

wherein Ar₁ is a substituted or unsubstituted phenyl group, or asubstituted or unsubstituted naphthyl group; Ar₂ is selected from thegroup consisting of an acetyl group, a benzoyl group, a 1,3,5-triazinylgroup, a SO₂—C₆H₅ group, and a SO₂—C₆H₄—CH₃ group; and M is selectedfrom the group consisting of a hydrogen atom, an alkali metal, anammonium, and an organic ammonium, M being a counter ion of the sulfonicacid group;

wherein each of Ar₃ and Ar₄ is independently a substituted orunsubstituted phenyl group, or a substituted or unsubstituted naphthylgroup group, at least one of Ar₃ and Ar₄ having a carboxyl group or asalt thereof, or a sulfonic acid group or a salt thereof; M is selectedfrom the group consisting of a hydrogen atom, an alkali metal, anammonium, and an organic ammonium, M being a counter ion of the sulfonicacid group; R₅ is a 1,3,5-triazinylene group; each of R₆ and R₇ isindependently selected from the group consisting of a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedalkenyl group, a substituted or unsubstituted aralkyl group, and anatomic group necessary to complete a perhydroxyazine ring together withN; and L is a bivalent organic connecting group.
 10. An ink setaccording to claim 9, wherein the first ink further contains at leastone of C. I. Acid Red 52 and C. I. Acid Red 289 as the coloringmaterial.
 11. An ink set according to claim 6, wherein the first inkcontains a dye represented by formula (I) and at least one of C. I. AcidRed 52 and C. I. Acid Red
 289. 12. An ink set according to any one ofclaims 1 to 3, wherein total content of all coloring materials in thefirst ink is 1.0% to 15.0% by weight of the first ink.
 13. An ink setaccording to any one of claims 1 to 3, wherein total content of allcoloring materials in the second ink is 0.1% to 5.0% by weight of thesecond ink.
 14. An ink set comprising a first ink and a second inkhaving a same color tone, wherein the second ink has a lower coloringmaterial content than the coloring material content of the first ink,the second ink is an aqueous ink containing a dye represented by thefollowing formula (I) as a sole coloring material, and the first ink isan aqueous ink containing a dye represented by formula (I) and at leastone of a dye represented by formula (II) and a dye represented byformula (III), as coloring materials:

wherein R₁ is a substituted or unsubstituted alkoxy group or asubstituted or unsubstituted aryl group; each of R₂ and R₄ isindependently a hydrogen atom or a substituted or unsubstituted alkylgroup; R₃ is selected from the group consisting of a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedalkoxy group, a substituted or unsubstituted aryloxy group, and ahalogen atom; X₁ is a carboxyl group or a salt thereof, or a sulfonicacid group or a salt thereof; and n is 1 or 2;

wherein Ar₁ is a substituted or unsubstituted phenyl group, or asubstituted or unsubstituted naphthyl group; Ar₂ is selected from thegroup consisting of an acetyl group, a benzoyl group, a 1,3,5-triazinylgroup, a SO₂—C₆H₅ group, and a SO₂—C₆H₄—CH₃ group; and M is selectedfrom the group consisting of a hydrogen atom, an alkali metal, anammonium, and an organic ammonium, M being a counter ion of the sulfonicacid group;

wherein each of Ar₃ and Ar₄ is independently a substituted orunsubstituted phenyl group, or a substituted or unsubstituted naphthylgroup, at least one of Ar₃ and Ar₄ having a carboxyl group or a saltthereof, or a sulfonic acid group or a salt thereof; M is selected fromthe group consisting of a hydrogen atom, an alkali metal, an ammonium,and an organic ammonium, M being a counter ion of the sulfonic acidgroup; R₅ is a 1,3,5-triazinylene group; each of R₆ and R₇ isindependently selected from the group consisting of a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedalkenyl group, a substituted or unsubstituted aralkyl group, and anatomic group necessary to complete a perhydroxyazine ring together withN; and L is a bivalent organic connecting group.
 15. An ink setaccording to claim 14, wherein the first ink further contains at leastone of C. I. Acid Red 52 and C. I. Acid Red 289 as the coloringmaterial.
 16. An ink set according to claim 14, wherein the first inkfurther contains C. I. Acid Red 289 as a coloring material.
 17. An inkset comprising a first ink and a second ink having a same color tone,wherein the second ink has a lower coloring material content than thecoloring material content of the first ink, the second ink is an aqueousink containing a dye represented by formula (I) as a sole coloringmaterial, and the first ink is an aqueous ink containing a dyerepresented by the following formula (I) and at least one of C. I. AcidRed 52 and C. I. Acid Red 289:

wherein R₁ is a substituted or unsubstituted alkoxy group or asubstituted or unsubstituted aryl group; each of R₂ and R₄ isindependently a hydrogen atom or a substituted or unsubstituted alkylgroup; R₃ is selected from the group consisting of a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedalkoxy group, a substituted or unsubstituted aryloxy group, and ahalogen atom; X₁ is a carboxyl group or a salt thereof, or a sulfonicacid group or a salt thereof; and n is 1 or
 2. 18. An ink set accordingto any one of claims 14 to 17, wherein total content of all coloringmaterials in the first ink is 1.0% to 15.0% by weight of the first ink.19. An ink set according to any one of claims 14 to 17, wherein totalcontent of all coloring materials in the second ink is 0.1% to 5.0% byweight of the second ink.
 20. An ink set according to any one of claims14 to 17, further comprising at least one color ink selected from thegroup consisting of a black ink, a cyan ink, and a yellow ink.
 21. Anink set according to any one of claims 1, 2, 14 and 17, wherein theresidual rates of the reflection density of images produced with thefirst and second inks are 80% or more.
 22. An ink set according to anyone of claims 1 to 3 and 14 to 17, wherein the ink set is used for anink jet printer.
 23. An ink set according to claim 22, wherein the inkjet printer is a bubble jet printer.
 24. An ink jet recording apparatuscomprising: ink storage portions storing a first aqueous ink and asecond aqueous ink having a same color tone respectively, wherein thefirst ink and the second ink contain at least one common coloringmaterial, the second ink has a lower coloring material content than thecoloring material content of the first ink, and a degree of fading of animage produced with the second ink is the same as or lower than a degreeof fading of an image produced with the first ink; and a head portionfor ejecting the inks.
 25. An ink jet recording apparatus comprising:ink storage portions storing a first aqueous ink and a second aqueousink having a same color tone respectively, wherein the first ink and thesecond ink contain at least one common coloring material, the second inkhas a lower coloring material content than the coloring material contentof the first ink, and an image produced with the second ink when it isleft under a condition that promotes fading has a residual rate ofreflection density that is equal to or greater than that of an imageproduced with the first ink; and a head portion for ejecting the inks.26. An ink jet recording apparatus comprising: ink storage portionsstoring a first ink and a second ink having a same color tonerespectively, wherein the second ink has a lower coloring materialcontent than the coloring material content of the first ink, the secondink is an aqueous ink containing a dye represented by formula (I) as asole coloring material, and the first ink is an aqueous ink containing adye represented by formula (I) and at least one of a dye represented byformula (II) and a dye represented by formula (III), as coloringmaterials:

wherein R₁ is a substituted or unsubstituted alkoxy group or asubstituted or unsubstituted aryl group; each of R₂ and R₄ isindependently a hydrogen atom or a substituted or unsubstituted alkylgroup; R₃ is selected from the group consisting of a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedalkoxy group, a substituted or unsubstituted aryloxy group, and ahalogen atom; X₁ is a carboxyl group or a salt thereof, or a sulfonicacid group or a salt thereof; and n is 1 or 2;

wherein Ar₁ is a substituted or unsubstituted phenyl group, or asubstituted or unsubstituted naphthyl group; Ar₂ is selected from thegroup consisting of an acetyl group, a benzoyl group, a 1,3,5-triazinylgroup, a SO₂—C₆H₅ group, and a SO₂—C₆H₄—CH₃ group; and M is selectedfrom the group consisting of a hydrogen atom, an alkali metal, anammonium, and an organic ammonium, M being a counter ion of the sulfonicacid group;

wherein each of Ar₃ and Ar₄ is independently a substituted orunsubstituted phenyl group, or a substituted or unsubstituted naphthylgroup, at least one of Ar₃ and Ar₄ having a carboxyl group or a saltthereof, or a sulfonic acid group or a salt thereof; M is selected fromthe group consisting of a hydrogen atom, an alkali metal, an ammonium,and an organic ammonium, M being a counter ion of the sulfonic acidgroup; R₅ is a 1,3,5-triazinylene group; each of R₆ and R₇ isindependently selected from the group consisting of a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedalkenyl group, a substituted or unsubstituted aralkyl group, and anatomic group necessary to complete a perhydroxyazine ring together withN; and L is a bivalent organic connecting group; and a head portion forejecting the inks.
 27. An ink jet recording apparatus comprising: inkstorage portions storing a first ink and a second ink having a samecolor tone respectively, wherein the second ink has a lower coloringmaterial content than the coloring material content of the first ink,the second ink is an aqueous ink containing a dye represented by formula(I) as a sole coloring material, and the first ink is an aqueous inkcontaining a dye represented by formula (I) and at least one of C. I.Acid Red 52 and C. I. Acid Red 289:

wherein R₁ is a substituted or unsubstituted alkoxy group or asubstituted or unsubstituted aryl group; each of R₂ and R₄ isindependently a hydrogen atom or a substituted or unsubstituted alkylgroup; R₃ is selected from the group consisting of a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedalkoxy group, a substituted or unsubstituted aryloxy group, and ahalogen atom; X₁ is a carboxyl group or a salt thereof, or a sulfonicacid group or a salt thereof; and n is 1 or 2; and a head portion forejecting the inks.
 28. An ink jet recording apparatus according to anyone of claims 24 to 27, wherein residual rates of reflection density ofimages produced with the first and second inks are 80% or more.
 29. Anink jet recording method comprising the step of applying a first aqueousink and a second aqueous ink having a same color tone to a recordingmedium, wherein the first ink and the second ink contain at least onecommon coloring material, the second ink has a lower coloring materialcontent than the coloring material content of the first ink, and adegree of fading of an image produced with the second ink is the same asor lower than a degree of fading of an image produced with the firstink.
 30. An ink jet recording method comprising the step of applying afirst aqueous ink and a second aqueous ink having the same color tone toa recording medium, wherein the first ink and the second ink contain atleast one common coloring material, the second ink has a lower coloringmaterial content than the coloring material content of the first ink,and an image produced with the second ink when it is left under acondition that promotes fading has a residual rate of reflection densitythat is equal to or greater than that of an image produced with thefirst ink.
 31. An ink jet recording method comprising the step ofapplying a first ink and a second ink having a same color tone to arecording medium, wherein the second ink has a lower coloring materialcontent than the coloring material content of the first ink, the secondink is an aqueous ink containing a dye represented by formula (I) as asole coloring material, and the first ink is an aqueous ink containing adye represented by formula (I) and at least one of a dye represented byformula (II) and a dye represented by formula (III), as coloringmaterials:

wherein R₁ is a substituted or unsubstituted alkoxy group or asubstituted or unsubstituted aryl group; each of R₂ and R₄ isindependently a hydrogen atom or a substituted or unsubstituted alkylgroup; R₃ is selected from the group consisting of a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedalkoxy group, a substituted or unsubstituted aryloxy group, and ahalogen atom; X₁ is a carboxyl group or a salt thereof, or a sulfonicacid group or a salt thereof; and n is 1 or 2;

wherein Ar₁ is a substituted or unsubstituted phenyl group, or asubstituted or unsubstituted naphthyl group; Ar₂ is selected from thegroup consisting of an acetyl group, a benzoyl group, a 1,3,5-triazinylgroup, a SO₂—C₆H₅ group, and a SO₂—C₆H₄—CH₃ group; and M is selectedfrom the group consisting of a hydrogen atom, an alkali metal, anammonium, and an organic ammonium, M being a counter ion of the sulfonicacid group;

wherein each of Ar₃ and Ar₄ is independently a substituted orunsubstituted phenyl group, or a substituted or unsubstituted naphthylgroup, at least one of Ar₃ and Ar₄ having a carboxyl group or a saltthereof, or a sulfonic acid group or a salt thereof; M is selected fromthe group consisting of a hydrogen atom, an alkali metal, an ammonium,and an organic ammonium, M being a counter ion of the sulfonic acidgroup; R₅ is a 1,3,5-triazinylene group; each of R₆ and R₇ isindependently selected from the group consisting of a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedalkenyl group, a substituted or unsubstituted aralkyl group, and anatomic group necessary to complete a perhydroxyazine ring together withN; and L is a bivalent organic connecting group.
 32. An ink jetrecording method comprising a step of applying a first ink and a secondink having a same color tone to a recording medium, wherein the secondink has a lower coloring material content than the coloring materialcontent of the first ink, the second ink is an aqueous ink containing adye represented by formula (I) as a sole coloring material, and thefirst ink is an aqueous ink containing a dye represented by formula (I)and at least one of C. I. Acid Red 52 and C. I. Acid Red 289:

wherein R₁ is a substituted or unsubstituted alkoxy group or asubstituted or unsubstituted aryl group; each of R₂ and R₄ isindependently a hydrogen atom or a substituted or unsubstituted alkylgroup; R₃ is selected from the group consisting of a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedalkoxy group, a substituted or unsubstituted aryloxy group, and ahalogen atom; X₁ is a carboxyl group or a salt thereof, or a sulfonicacid group or a salt thereof; and n is 1 or
 2. 33. An ink jet recordingmethod according to any one of claims 29 to 32, wherein the inks areejected from orifices in response to recording signals so as to adhereto a recording medium.
 34. An ink jet recording method according toclaim 33, wherein the inks are ejected from orifices by applying thermalenergy thereto in response to recording signals so as to adhere to therecording medium.
 35. An ink jet recording method according to any oneof claims 29 to 32, wherein the residual rates of the reflection densityof images produced with the first and second inks are 80% or more.
 36. Arecording unit comprising: an ink container section containing inks; anda head section for ejecting the inks, wherein the inks constitute an inkset according to claim
 22. 37. A recording unit according to claim 36,wherein the head section comprises heads for ejecting the inks byapplying thermal energy to the inks.
 38. An ink cartridge comprising anink container section containing inks, wherein the inks constitute anink set according to any one of claims 1 to 3 and 14 to 17.